Four New Species of Paspalum (Poaceae, Paniceae) from Central Brazil, and Resurrection of an Old One

Gabriel H. Rua,1,4 José F. M. Valls,1 Dalva Graciano-Ribeiro,2 and Regina C. Oliveira3 1EMBRAPA Recursos Genéticos e Biotecnologia, Parque Estação Biológica, Final W-5 Norte, Caixa Postal 02372, CEP 70770-900 Brasília, DF, Brazil 2Universidade de Brasília, Instituto de Ciências Biológicas, Departamento de Botânica, Campus Universitário, Asa Norte, Caixa-Postal 04457, 70910-900 Brasília, DF, Brazil 3Herbário Dárdano de Andrade Lima, Universidade Federal Rural do Semi-Árido, Caixa Postal 137, CEP 59600-970, Mossoró, RN, Brazil 4Author for correspondence, present address: Cátedra de Botánica Agrícola, Facultad de Agronomía, Universidad de Buenos Aires, Av. San Martín 4453, C1417DSE Buenos Aires, Argentina ([email protected])

Communicating Editor: Gregory M. Plunkett

Abstract—Four new Brazilian species from the genus Paspalum are described and illustrated: P. phaeotrichum, P. vexillarium, P. veredense, and P. clipeum. Paspalum phaeotrichum is an annual with no obvious affinity to any known species of Paspalum, although it shares several characters with species of both P. subg. Ceresia and the ’Bertoniana’ group. Paspalum vexillarium is presumably related to P. ceresia, with which it has been confused. Paspalum veredense shows affinities with both P. ellipticum and P. erianthoides. Paspalum clipeum is probably related to annual species of the ’Plicatula’ group, although it lacks the dark brown upper florets typical of that group. Moreover, P. spissum, a species currently considered as a synonym under P. carinatum, is recognized on the basis of vegetative morphology, phenology and habitat. Keys to the treated species are provided when relevant, as well as a distribution map. Resumo—Quatro novas espécies de Paspalum do Brasil são descritas e ilustradas: P. phaeotrichum, P. vexillarium, P. veredense,eP. clipeum. Paspalum phaeotrichum é uma espécie anual sem afinidades obvias com outras espécies do gênero, embora compartilhe vários caracteres com P. subg. Ceresia e com o grupo ’Bertoniana’. Paspalum vexillarium é supostamente relacionada a P. ceresia, com a qual tem sido confundida. Paspalum veredense tem afinidades com P. ellipticum e P. erianthoides. Paspalum clipeum é provavelmente relacionada às espécies anuais do grupo ’Plicatula’, embora não apresente os antécios superiores de cor marrom escura, típicos desse grupo. Além disso, P. spissum, uma espécie atualmente considerada como sinônimo de P. carinatum, é reabilitada com base na morfologia vegetativa, fenologia e habitat. São fornecidas chaves para as espécies tratadas, quando relevante, assim como um mapa de distribuição.

Keywords—Brazilian flora, Cerrado, grasses, Panicoideae, taxonomy.

Paspalum L. comprises about 350 species of grasses mostly Chase was examined at BAA and SI for comparison. Leaf samples for distributed in tropical and warm-temperate areas of the anatomical sections from herbarium specimens were rehydrated according to the method described by Voster (1990) with few modifications. Americas (Clayton and Renvoize 1986; Zuloaga and Morrone Cross sections were obtained using a Ranvier microtome, stained with 2005; Denham 2005). They are recognized by their dorsiven- Alcian blue and safranin 1% and mounted using a synthetic resin (Paiva tral raceme-like partial inflorescences, by their plano-convex et al. 2006). Anatomical micrographs were obtained using a Zeiss Ax- spikelets with the upper lemma adaxial, and, in most cases, ioscop MC80DX microscope. Micrographs of the upper lemma surface were taken using a Zeiss DSM 962 scanning electron microscope (SEM). by the lacking of the lower glume. Within the Panicoideae, the genus Paspalum belongs to a clade characterized by a basic chromosome number of x = 10 (Giussani et al. 2001) and TAXONOMIC TREATMENT is related to other genera having an NADP-ME photosyn- thetic pathway. Paspalum phaeotrichum Valls, G. H. Rua, Graciano-Ribeiro, Species of Paspalum are, in large part, responsible for much & R. C. Oliveira, sp. nov.—TYPE (here designated): of the biodiversity of grassland ecosystems in South America, BRAZIL. Bahia: Mun. Riachão das Neves, entrada de which are strongly threatened by the expansion of agricul- fazenda ca. 20 km N de Barreiras pela estrada antiga, 2 ture. Among them, the Brazilian Cerrado is certainly a km N da ponte sobre o Rio Branco, 31 Mar 1983, J. F. M. hotspot of grass diversity (Warming 1973; Mendonça et al. Valls, A. Krapovickas, R. F. A. Veiga, & G. Pereira-Silva 7049 1998). A number of new grass genera and species have been (holotype: CEN!; isotypes: BAA!, L!, RB!, SI!, US!). described from this region in recent years, including several species of Paspalum (Burman 1980; Davidse and Filgueiras A omnibus speciebus notis distincta, tamen P. lilloi Hack. 1993; Filgueiras and Davidse 1994; Filgueiras 1995; Davidse flosculo molli, laminis foliorum costatis aliquantum similis, et al. 2001; Filgueiras et al. 2001, Morrone and Zuloaga 2003). sed habitu annuo, omnibus partibus multo minoribus differt. While identifying grasses collected in Cerrado areas of cen- Annuals. Culms 18–28 cm tall, 0.8–0.9 mm diam, erect to tral Brazil, four new species of Paspalum were found. They decumbent, freely branching, some culms proximally creep- are here described, illustrated, and compared with related ing, with branches rooting at the base, the main axis coming species. Moreover, P. spissum, a species currently considered to flower; internodes glabrous, the basalmost purple, other- a synonym of P. carinatum, is recognized on the basis of veg- wise pale; nodes glabrous, purple-tinged. Leaf sheaths etative morphology, phenology and habitat. keeled, striate, long-ciliate at the top of margins, otherwise glabrous, the proximal sheaths 1–1.5 cm long, purple-tinged, the distal sheaths up to 6 cm long. Ligules 0.5–0.7 mm long, MATERIALS AND METHODS membranous, acute, glabrous, erose, without a pseudoligule. Descriptions and illustrations were based on field collections and her- Blades 4.5–5.5 cm long, ca. 2 mm wide, lanceolate-acuminate, barium material (CEN, IBGE, UB). Andean material of P. ceresia (Kuntze) flat, the base narrower than the leaf sheath, sharply ribbed

267 268 SYSTEMATIC BOTANY [Volume 33

FIG. 2. Leaf blade anatomy in cross section, general view (left) and detail of a portion (right). A, B. Paspalum phaeotrichum (Valls et al. 7049). C, D. Paspalum vexillarium (Amaral et al. 28). E, F. Paspalum veredense (Rua et al. 695).

FIG.1. Paspalum phaeotrichum (from Valls et al. 7049). A. Habit. B. Spikelet, adaxial view. C. Spikelet, abaxial view. D. Upper glume, adaxial overlapping marginal flaps; lodicules 2; stamens 3, anthers view. E. Lower lemma, abaxial view. F. Upper floret, adaxial view. G. 2.1–2.2 mm long, yellowish; stigmas 2, pale, plumose. Cary- Upper floret, abaxial view. H. Caryopsis, hilum side. I. Caryopsis, embryo side. J. Caryopsis, lateral side. K. Portion of the rachis, abaxial view. opsis 1.8 mm long, ca. 1 mm wide, plano-convex, obovate, slightly emarginate at apex, pale; hilum ca. 0.8 mm long., adaxially; the margins with a few proximal cilia, otherwise linear-elliptical. Figure 1. glabrous; cauline blades reduced, the most distal ca. 1 cm Leaf Anatomy—(Fig. 2A, B). Leaf blade expanded in cross long. Peduncles 4.5–9 cm long, compressed, glabrous, pale to section, sharply ribbed/furrowed adaxially. Midrib incon- purple-tinged. Inflorescences exserted; main axis not pro- spicuous, with a single first-order vascular bundle. Cuticle longed above the racemes; ‘racemes’ 2–4 cm long, 2, conju- thin. Adaxial epidermis with typical epidermal cells, bicellu- gate, ascending to divaricate; pulvini hirsute; rachis of the lar microhairs, 3–5 fan-shaped bulliform cells, stomata, and racemes ca. 0.4 mm wide, glabrous, flexuous, triquetrous, narrowly 3-winged, ending in a terminal spikelet, the nerves green, otherwise pale; spikelets 4.0–4.1 mm long, 1.1–1.4 mm wide, narrowly ovate, solitary, sessile, loosely 2-seriate, deciduous at maturity, dorsiventrally compressed. Lower glumes lacking. Upper glumes as long as the spikelets, ca. 2.1 mm wide, ovate, membranous-hyaline, pale, 7-nerved, the two outer nerve pairs close to the margins, the proximal half convex, corrugate, densely pilose with pale hairs intermingled with longer and stiffer, golden-brown cilia up to 3 mm long; the distal half depressed, somewhat ornamented with longitudinal purple stripes, pilose along the lateral nerves, otherwise glabrous, the involute margins covering the margins of the lower lemma; the base widely attenuate, the apex acute but somewhat rounded at the very tip. Lower lemmas ca. 4 mm long, 1 mm wide, narrowly ovate, flat, acute at apex, 5-nerved, the lateral nerves close to the margins, densely pilose at the proximal portion. Upper florets 3.1–3.3 mm long, 1–1.1 mm wide, narrowly ellipsoidal, flattened, hyaline, pale, glabrous, the upper lemma faintly

5-nerved, slightly shorter that the palea and not enclosing the FIG. 3. Distribution map of Paspalum phaeotrichum, P. vexillarium, P. palea apex, so that the floret remains open, the palea with veredense, P. clipeum, and P. spissum. 2008] RUA ET AL.: NEW PASPALUM FROM BRAZIL 269 silicified cells. Mesophyll consisting of radial chlorenchyma finity with any known species of Paspalum. Morphologically cells. Three orders of vascular bundles present, each sur- it seems allied to species of P. subg. Ceresia (Pers.) Rchb., rounded by a single bundle sheath of relatively large, thin- because of its soft, distally gaping upper floret, and the hair walled parenchyma cells, the bundles separated by 1 or 2 pattern in the basal portion and margins of the upper glume. parenchyma cells. Sclerenchyma both adaxial and abaxial However, the rachis of the ‘racemes’ are slender, triquetrous, girders along ribs, but only abaxially at intercostal regions. narrowly 3-winged, with the lateral margins not distinctly Distribution and Habitat—(Fig. 3). The new species was developed. The characteristics of open upper florets, that are found near Barreiras, in the state of Bahia, in areas of tran- shorter than the upper glumes and lower lemmas, the pres- sition between Cerrado and Caatinga vegetation. Paspalum ence of linear-elliptical hilums, and leaf blades conspicuously phaeotrichum is known only from the type collection. ribbed suggest an affinity with P. lilloi Hack. and P. bertonii Etymology—The specific epithet refers to the golden- Hack., both from Paspalum ’Bertoniana’ group. brown setaceous cilia of the upper glume. The following key separates the new species from other Observations—Paspalum phaeotrichum has no obvious af- putatively related groups in the genus Paspalum.

1. Apex of the upper palea enclosed by the inrolled borders of the upper lemma...... Paspalum spp. (most species) 1. Apex of the upper palea free, not enclosed by the upper lemma ...... 2 2. Rachis winged, 0.8–12 mm wide, the lateral margins conspicuously developed; hilum mostly punctiform to elliptical; adaxial surface of the leaf blades smooth ...... Paspalum subg. Ceresia (Pers.) Rchb. 2. Rachis trichetrous to obscurely winged, 0.4–0.7 mm wide; hilum linear-elliptical; adaxial surface of the leaf blades with conspicuous ribs and furrows ...... 3 3. Perennials; inflorescence branches separated by conspicuous internodes; upper glumes with whitish hairs only; upper florets membranaceous; plants from stony river banks ...... Paspalum ‘Bertoniana’ group 3. Annuals; inflorescence branches conjugate; upper glumes with golden-brown cilia intermingled with whitish hairs; upper florets hyaline; plants from temporarily dry sites ...... P. phaeotrichum nov. sp.

Paspalum vexillarium G. H. Rua, Valls, Graciano-Ribeiro, & gitudinally folded, glabrous, conspicuously winged, ending R. C. Oliveira, sp. nov.—TYPE (here designated): BRA- in a naked point, the middle portion greenish to purple, the ZIL. Distrito Federal: APA da Cafuringa, 15°27Ј27Љ S, wings orange-ferruginous; pedicels minute, puberulous. 47°58Ј00Љ W, 22 Mar 2006, A. C. Amaral, E. S. G. Guarino, Spikelets solitary, densely imbricate in 2 series, dorsiven- G. Pereira-Silva, & J. R. Santos 28 (holotype: CEN!; iso- trally compressed. Lower glumes lacking. Upper glumes types: BAA!, K!, L!, MO!, RB!, SI!, US!). 2–2.9 mm long, 1–1.3 mm wide, ovate, membranous, pale to Paspalum membranaceum Lam. var. inaequiglume Döll, in Mart., Fl. Bras. 2(2): 94. 1877.—TYPE: BRAZIL. Goiás: campos between Natividade e Conceição, Feb 1840, G. Gardner 4029 (lectotype: designated by Denham et al. (2002), B-photograph!).

P. ceresia affine sed lemmate inferiore manifeste binervio, gluma superiori conspicue breviore, rhizomate cataphyllis nullis differt. Caespitose perennials. Base of tillers U-shaped, composed of a variable number of short internodes, the first node with a brownish, scale-like prophyll, the next one bearing an additional cataphyll, the following nodes with foliage leaves, the dead sheaths of which remain covering the base of the tillers. Culms 60–75 cm tall, ca. 1 mm diam, erect, branched at the lowermost nodes; internodes 3–7, glabrous to faintly puberulous, reddish; nodes mostly bearded. Leaf sheaths up to 11 cm long, distally keeled, glabrous to distally hirsute, greenish, the outer surface striate in dry material, sometimes purple-tinged, the margins membranous. Ligules ca. 0.3 mm long, membranous, rounded to obtuse, hyaline, glabrous, erose, without pseudoligule. Blades up to 25 cm long, 3–5 mm wide at flowering, up to 10 mm wide in early regrowth, linear, ribbon-like, ascending, flat to folded and apparently filiform, the base continuing with the leaf sheath, acuminate at apex, somewhat glaucous, glabrous to coarsely hirsute on the adaxial surface, glabrous abaxially; the margins finely scabrous and ciliate along the proximal third; upper blades reduced. Peduncles 9–17 cm long, terete, puberulous, pur- FIG.4. Paspalum vexillarium (I and J from Rua et al. 642, otherwise from plish. Inflorescences mostly exserted; main axis 2–6 cm long, Amaral et al. 28). A. Habit and detail of the inflorescence. B. Spikelet, adaxial view. C. Spikelet, abaxial view. D. Upper glume, abaxial view. E. truncate or ending in a short naked point; ‘racemes’ 2–6cm Lower lemma, abaxial view. F. Upper floret, adaxial view. G. Upper long, (1)2–6, ascending, alternate along the inflorescence axis; floret, abaxial view. H. Portion of the rachis, abaxial view. I. Caryopsis, pulvini pubescent; rachis of the racemes 5–12 mm wide, lon- hilum side. J. Caryopsis, embryo side. 270 SYSTEMATIC BOTANY [Volume 33 ferruginous, 3-nerved, the nerves submarginal, densely silky- Distribution and Habitat—(Fig. 3). P. vexillarium is a com- pilose at the base and along the margins, otherwise glabrous, mon species found in pebbly or rocky soils in areas of Cerrado the marginal hairs forming two conspicuous lateral tufts pre- vegetation, comprising the Brazilian states of Pará, Maranhão, ceding a row of stouter, tubercle-based cilia up to 2.5 mm in Piauí, Goiás, Minas Gerais, Tocantins, and Distrito Federal. the distal portion; the margins inrolled, the base attenuate, Chromosome Number—Chromosome counts in two para- the apex acute and slightly recurved, glabrous. Lower lem- types (Rua & Oliveira 632 & 642) were 2n=40 (Pozzobon et al. mas 1.6–2.3 mm long, 0.4–0.5 mm wide, oblong-obovate, dor- in press, under Paspalum aff. ceresia). sally concave, obtuse to rounded at apex, strongly 2-nerved, Etymology—The specific epithet means ‘standard-bearer’, indumentum as in the upper glume. Upper florets 2–2.1 mm and refers to the flag-like appearance of the rachis. long, 0.7–0.8 mm wide, narrowly ovate to ellipsoidal, shortly Additional Material Examined—BRAZIL. Goiás: Mun. Alto Paraiso, acuminate, deciduous at maturity, dorsiventrally com- Alto Paraiso-Colinas, próximo do Vale da Lua,a6kmdeSão Jorge, 21 Jul pressed, membranous-hyaline, whitish, the upper lemma 1994, Boechat & Filgueiras 101 (IBGE); Chapada dos Veadeiros, ca. 5 km SE of São Jorge, Vale da Lua, 14°09Ј39Љ S, 47°46Ј14Љ W, 898 m, 11 Jul 2005, Rua faintly 3-nerved, both lemma and palea shortly pubescent on & Oliveira 642 (CEN); Mun. Barro Alto, Barro Alto, 8 Jul 1994, Brina s.n. the distal portion; lodicules lacking; stamens 3, anthers ca. 2.2 (CEN); Mun. Campos Belos, estrada de chão para Pouso Alto, 12°58Ј33Љ mm long, yellow with purple marks; stigmas 2, pale, plumose. S, 46°28Ј05Љ W, 740 m, 23 Apr 2001, Pereira & Cardoso 2552 (IBGE); Mun. Caryopses ca. 1.1 mm long, ca. 0.6 mm wide, obovate, dorsi- Colinas do Sul, ca. 23 km da entrada Sul do canteiro da A.H.E. Serra da Ј Љ Ј Љ ventrally compressed, slightly emarginate at apex, stramine- Mesa, 13°53 37 S, 48°07 39 W, 500 m, 12 Sep 1997, Oliveira & al. 805 (CEN); Mun. Flores de Goiás, Serra do Morcego, wooded valley, córrego ous; hilum ca. 0.3 mm long, narrowly elliptical. Figures 4, 5A. Estrema, ca. 35 km NE of Formosa, 800 m, 22 Apr 1966, Irwin et al. 15248 Leaf Anatomy—(Fig. 2C, D). Leaf blade expanded in cross (IBGE, UB); Mun. Niquelândia, Macedo, ca. 18 km N de Niquelândia, 13 section. Cuticle somewhat thick. Adaxial epidermis with Apr 1992, Filgueiras 2280 (IBGE, UB); loc. de Macedo, ca. 20 km de Ј Ј typical epidermal cells, bicellular microhairs, macrohairs, Niquelândia, 14°18 S, 48°23 W, 4 Aug 1992, Filgueiras & Lopes 2433 (IBGE); 2 km da estrada de chão para o Macedo Velho, 14°21Ј03Љ S, cushion hairs, inflated bulliform cells, stomata and silicified 48°24Ј52Љ W, 25 Apr 1995, Oliveira et al. 305 (IBGE); Companhia de Níquel cells. Mesophyll consisting of radial chlorenchymatous cells. Tocantins-CNT, ca. 1 km após a mina de níquel, descendo no lado es- Two orders of vascular bundles present, all of them sur- querdo da estrada, 14°21Ј29Љ S, 48°23Ј11Љ W, 12 Apr 1996, Oliveira et al. 516 rounded by a single bundle sheath of relatively large, thin- (IBGE); Macedo, ca. 1 km abaixo da mina de níquel, 14°21Ј29Љ S, 48°23Ј11Љ walled parenchyma cells; the bundles separated by 1 or 2 W, 29 May 1996, Oliveira et al. 598 (IBGE); ca. 4 km de Macedo Velho, próximo à bica, 14°21Ј34Љ S, 48°24Ј38Љ W, 30 May 1996, da Silva & Nunes parenchyma cells. First order vascular bundles with abaxial de Jesus 3017 (IBGE); ca. 8 km do trevo de Niquelândia em direção à and adaxial sclerenchyma extensions. Abaxial sclerenchyma Companhia de Níquel Tocantins, 14°05’ S, 48°22’ W, 25 Oct 2000, Oliveira caps associated with second order vascular bundles. & Moraes 1435 (CEN); Estrada Niquelândia-Macedo, ca. 10 km N de

FIG. 5. Field photographs of Paspalum species. A. Paspalum vexillarium in Vale da Lua (’Moon Valley’), Mun. Alto Paraiso, Goiás, Brazil. B. A population of Paspalum veredense in a ’vereda’ margin in the Jalapão region, Tocantins, Brazil. C. Paspalum clipeum in a deciduous forest (’mata-seca’) area in Simolândia, Goiás, Brazil. D. Paspalum spissum (left) and P. carinatum (right) in Cerrado areas in the Jalapão region, Tocantins, Brazil. 2008] RUA ET AL.: NEW PASPALUM FROM BRAZIL 271

Niquelândia, 14°22Ј32.5Љ S, 48°25Ј46.2Љ W, 863 m, 10 Jul 2005, Rua & such a distinction was not made, because the authors felt it Oliveira 632 (CEN); Maranhão: Mun. Loreto, Ilha de Balsas, region be- was based on “a variable character according to the degree of tween the Balsas and Parnaíba rivers, 35 km S of Loreto, several hundred meters W of main house of Fazenda Morro along trail to “Gigante”, maturity of spikelets” (p. 363). Leaf shape and width was also 07°23Ј S, 45°04Ј W, 300–350 m, 25 Feb 1970, Eiten & Eiten 10789 (UB); disregarded as a valuable taxonomic character, because the Minas Gerais: Mun. Montezuma, Retiro, ca. 16 km da cidade em direção authors felt they exhibited “a considerable variation,” rang- Ј Љ Ј Љ a Mato Verde, 15°18 23 S, 42°31 25 W, 900 m, 17 Mar 1994, Souza et al. ing from “filiform to linear and rigid,” to “filiform and lan- 5548 (UB); Piauí: Mun. Corrente, 500 m ao sul da ponte sobre o rio Corrente na BR-135, 10°27’ S, 45°10’ W, 460 m, 3 Apr 1983, Valls et al. 7109 ceolate in a single specimen,” to lanceolate, up to 2 cm wide. (CEN); Mun. Gilbués, Gilbués, 14 Mar 1979, Delarco s.n. (Herb. G. Barroso Curiously, these authors overlooked the strong correlation 363, CEN); Gilbués, area degradada em avançado processo de desertifi- between subequal vs. unequal upper glumes and lower lem- cação, 8 Mar 1988, Filgueiras & Rodrigues 1342, 1347, 1350 (IBGE); To- mas, lanceolate vs. narrowly elliptical to lineal leaves, and cantins: Mun. Tocantinópolis, estrada vicinal junto à Ferrovia Norte-Sul, km 18 no sentido Darcinópolis, 06°38Ј50Љ S, 47°29Ј56Љ W, 190 m, 21 Feb geographical distribution. Indeed, all the specimens that they 2005, Pereira-Silva et al. 9457 (CEN). cited as having “filiform” leaves are from Brazil, as is all the Observations—Paspalum vexillarium has long been con- material available to us and now included in the new species. fused with P. ceresia, a species growing in Andean slopes of The Döll’s epithet inaequiglume cannot be used at the species Ecuador, Peru, Bolivia and NW Argentina. Döll (1877) dis- level because the binomial P. inaequiglume Parodi already tinguished P. vexillarium and P. ceresia at the varietal level exists; hence the new epithet vexillarium is here proposed for (under P. membranaceum var. inaequiglume Döll and var. aequi- this species. glume Döll, respectively), on the basis of the relative length of The following key separates the new species from other upper glumes and lower lemmas. Nevertheless, in the recent Paspalum species in P. subg. Ceresia with membranous ra- revision of Paspalum subg. Ceresia by Denham et al. (2002), chises more than 3.5 mm wide and solitary spikelets.

1. Spikelets awned ...... 2 2. Dwarf plants up to 40 cm tall; spikelets 1.1–2.2 mm long ...... P. longiaristatum Davidse & Filg. 2. Plants more than 70 cm tall; spikelets 3.8–4.5 long ...... P. biaristatum Filg. & Davidse 1. Spikelets not awned ...... 3 3. Spikelets 5–7 mm long; upper florets conspicuously shorter than the spikelets ...... 4 4. Upper glumes winged, cordate at base; upper florets sessile ...... P. aspidiotes Trin. 4. Upper glumes not winged or cordate; upper floret stipitate ...... P. lanciflorum Trin. 3. Spikelets up to 4 mm long; upper florets as long as or slightly shorter than the spikelets ...... 5 5. Rachises 3.5–4 mm wide; spikelets occasionally paired; culms many-noded ...... 6 6. Plants caespitose; culms freely branched at the upper nodes after flowering of the main axis; spikelets 2.3–3 mm long, with an annular thickening at the base; a few marginal hairs longer than the rest; lower lemmas pilose only at the upper margins ...... P. heterotrichon Trin. 6. Plants rhizomatous; culms unbranched, at least at the upper nodes; spikelets 3.5–4.2 mm long, without an annular thickening at the base; marginal hairs ± uniform; lower lemmas pilose at the margins and the basal portion...... P. gracielae Sulekic 5. Rachises 5–10 mm wide; spikelets always solitary, without an annular thickening at the base; culms few-noded ...... 7 7. Inflorescences with 1 or 2 primary branches, if 2 conjugate; pedicels with a crown of hairs toward the apex; upper florets short-stipitate; lodicules 2; blades filiform, 0.1–0.3 cm wide ...... P. stellatum Humb. & Bonpl. ex Flüggé 7. Inflorescences with (1)2–7 primary branches, alternate along the main axis; pedicels without a crown of hairs toward the apex; upper florets sessile; lodicules absent; blades linear-filiform to linear-lanceolate, 0.5–2 cm wide ...... 8 8. Spikelets 2.9–4.0 mm long., 1.2–1.4 mm wide; upper glumes flat; lower lemmas 93–97% as long as the upper glumes, ca. 1 mm wide, flat to slightly convex, acute, pilose throughout on the abaxial surface, nerves slightly prominent; proximal portion of the tillers shortly plagiotropic, covered with several cataphylls; culms freely branching; leaf blades 0.5–1(–2) cm wide, flat; Eastern Andean slopes in Ecuador, Perú, Bolivia and NW Argentina ...... P. ceresia (Kuntze) Chase 8. Spikelets 2.2–2.9 mm long., ca. 1 mm wide, upper glumes with inrolled margins and slightly recurved apex; lower lemmas 64–84% as long as the upper glumes, 0.4–0.5 mm wide, concave, obtuse, glabrous and glossy on the abaxial surface, lateral nerves very prominent; tillers orthotropic, covered with the old proximal leaf sheaths; culms unbranching or branching just at the lowermost nodes; leaf blades 0.3–0.5 cm wide, flat to involute; central Brazil ...... P. vexillarium nov. sp.

Paspalum veredense G. H. Rua, R. C. Oliveira, Valls, & Gra- leaves. Culms 70–110 cm tall, ca. 2 mm diam, erect, un- ciano-Ribeiro, sp. nov.— TYPE (here designated): BRA- branched; internodes 3 or 4, glabrous, terete, hollow, pale; ZIL. Tocantins: Mun. Mateiros, Região do Jalapão, es- nodes dark. Proximal leaf sheaths 7–12 cm long, the distal trada Mateiros-SãoFélix, ca. povoado da Mumbuca, ver- ones longer, slightly keeled, hirsute at the base and the apical eda da Extrema, 10°21Ј13.4Љ S, 46°36Ј49.9Љ W, 442 m, 9 margin, otherwise glabrous, striate in dry material. Ligules Dec 2005, G. H. Rua, I. B. Figueiredo, J. M. de Rezende, R. F. ca. 0.7 mm long, membranous, obtuse, hyaline, glabrous, Lima 695 (holotype: CEN!; isotypes: BAA!, RB!, US!). without a pseudoligule. Blades 40–65 cm long, 1–1.5 mm P. elliptico Döll affine sed foliis farctis teretibus, spiculis wide, solid, elliptical in cross section, junciform, somewhat minoribus acutis vel acuminatis, lemmate inferiori trans- bending, the base continuing with the leaf sheath, slightly verse-plicato, flosculo lemmate inferiori breviore, inconspi- pungent at apex, glaucous, hirsute at the very base, otherwise cue papilloso differt. glabrous; upper blades reduced. Peduncles 25–40 cm long, Caespitose perennials forming dense clumps. Base of tillers terete, glabrous, pale. Inflorescences long exserted; main axis forming short, curved rhizomes bearing strong, thick roots up to ca. 2 cm long, prolonged into a terminal ‘raceme’ 2–3 mm diam, composed of several short internodes, the first shorter than the lateral ones or, more rarely, ending in a short node with a brownish, scale-like prophyll, the next one or naked point; ‘racemes’ 2–6, the lowermost 4.5–11.5 cm long, two nodes bearing cataphylls, the following ones with foliage erect, conjugate to subdigitate; pulvini hirsute; rachis of the 272 SYSTEMATIC BOTANY [Volume 33 racemes 0.7–0.9 mm wide, scabrous, somewhat flexuous, ending in a spikelet, greenish, the midnerve striking, pale; pedicels 0.5–1 mm long, puberulous, narrowly winged; spikelets 3.8–4.8 mm long, 1.2–1.4 mm wide, solitary, imbricate in 2 series, plano-convex. Lower glumes lacking. Upper glumes as long as the spikelets, 1.3–1.5 mm wide, narrowly ovate, membranous, 5-nerved, nerves green, the lateral nerves close to the glume margins, region between nerves pale, glaucous, somewhat crumpled, the marginal hairs up to 2 mm long, whitish, otherwise glabrous, margins involute, covering the margins of the lower lemma, the base truncate, FIG. 7. Scanning electron micrographs of the upper lemma epidermis. the apex acute to shortly acuminate. Lower lemmas 3.7–4.6 A. Paspalum veredense (Rua et al. 695, CEN). B. P. ellipticum (Souza et al. mm long, not as pilose as the glume, conspicuously wrinkled 7414, CEN). between nerves but otherwise similar to it. Upper florets 3.5– 3.8 mm long, 1.2–1.5 mm wide, narrowly elliptical, slightly shorter than the lower lemmas, plano-convex, coriaceous, lar bundles with sclerenchyma extensions; the bundles sepa- pale, glabrous, finely papillose with papillae 10–15 ␮m diam, rated by 1 or 2 parenchyma cells. Strands of sclerenchyma acute but blunt at the very apex, the upper lemmas faintly occur joining the margins. Parenchymatous medulla of very 3-nerved, the cucullate apex of the lemma clasping the palea thin-walled cells. apex; lodicules 2; stamens 3, anthers ca. 1.8 mm long, purple; Distribution and Habitat—(Figs. 3, 5B). This species forms stigmas 2, purple, plumose. Caryopses not seen. Figure 6. monospecific stands in moist grasslands (‘campo úmido’) Leaf Anatomy—(Fig. 2E, F). Leaf blades elliptical in cross along the margins of permanent swamp areas characterized section, solid cuticle thickened. Epidermis with typical epi- by the occurrence of the Buriti palm (Mauritia flexuosa L.f.), dermal cells, bicellular microhairs, hooks, stomata and silici- locally known as ‘veredas’, in the Brazilian states of Maran- fied cells. Mesophyll consisting of radial parenchyma cells. hão, Piauí, Goiás, and Tocantins. Three orders of vascular bundles present, all of them sur- Etymology—The epithet refers to the ‘veredas’, the Brazil- rounded by a single bundle sheath of relatively large, thin- ian name for permanent swamp areas along small rivers and walled parenchymatous cells. First- and second-order vascu- creeks, characterized by the occurrence of Mauritia flexuosa,in the margins of which the new species grows. Additional Material Examined—BRAZIL. Bahia: Mun. Correntina, vereda do Alegre, proximo à cabeceira do córrego Alegre, 22 km de Cor- rentina, 13°20Ј S, 44°40Ј W, 600 m, 1 Nov 1994, Oliveira & Werneck 277 (CEN); Maranhão: Mun. Balsas, Projeto Geral de Balsas, 07°35Ј S, 46°05Ј W, 300 m, 20 Nov 1995, Oliveira & Pereira-Silva 366 (CEN); Projeto Geral de Balsas, 07°35Ј S, 46°05Ј W, 300 m, 27 Nov 1997, Oliveira & Pereira-Silva 637 (IBGE); Geral de Balsas, campo úmido 06 (U6), 20 Mar 2000, Oliveira & al. 1401 (CEN); Tocantins: Mun. Dianópolis, nos arredores do acam- pamento, na margem direita do rio Limoeiro, confluência com o rio Palmeira, 11°31Ј00Љ S, 42°24Ј38Љ W, 630 m, 27 Sep 2003, Scariot et al. 879 (CEN); Mun. Mateiros, Região do Jalapão, estrada Mateiros-SãoFélix, ca. povoado da Mumbuca, vereda do Bebedouro, 10°22Ј29Љ S, 46°36Ј28Љ W, 444 m, 7 Dec 2005, Rua & al. 670 (CEN); Região do Jalapão, estrada Mateiros-SãoFélix, ca. povoado da Mumbuca, vereda do Velho, 10°23Ј06.6Љ S, 46°36Ј59.7Љ W, 479 m, 8 Dec 2005, Rua & al. 679 (CEN). Observations—(Figs. 2E, 7). Paspalum veredense is presumably related to P. ellipticum Döll and to P. erianthoides Lindm. It has sometimes been confused with P. ellipticum in herbarium identifications, and the specimens Oliveira & Werneck 277 and Oliveira & Pereira-Silva 366 were cited earlier as ref- erence material for this species (Oliveira and Valls 2002). The spikelets of P. veredense resemble those of P. ellipticum, from which they can be distinguished by being shorter, acute- acuminate, with plicate lower lemmas and upper florets shorter than lower lemmas, inconspicuously papillose in macroscopic observation (Fig. 7). Paspalum veredense is a ro- bust plant forming dense tussocks, with strong, densely packed rhizomes, thick roots and very distinctive stout, junciform, and solid leaf blades (Fig. 2E) resembling those of P. erianthoides, whereas the leaf blades of P. ellipticum are filiform-conduplicate (Aliscioni 2000). The following key separates the new species from other FIG.6. Paspalum veredense (from Rua et al. 695). A. Habit. B. Leaf apex. Paspalum species with pilose spikelets, inflorescences with C. Upper glume, abaxial view. D. Upper glume, adaxial view. E. Lower lemma, abaxial view. F. Upper floret, adaxial view. G. Upper floret, ab- two or more primary branches, and filiform to junciform axial view. H. Flower. I. Portion of the rachis with spikelets, adaxial view. leaves (groups ‘Notata’ and ‘Eriantha’ p.p.). 2008] RUA ET AL.: NEW PASPALUM FROM BRAZIL 273

1. Spikelets paired; inflorescence primary branches scattered along the main axis, appressed ...... P. erianthoides Lindm. 1. Spikelets solitary inflorescence primary branches conjugate or fasciculate ...... 2 2. Leaf blades filiform-conduplicate to sublanceolate, v-shaped in cross section, 0.2–1.5 mm wide; spikelets elliptical, mostly 4.5–5 mm long., upper glumes and lower lemmas obtuse to short-apiculate, as long as the upper florets, lower lemmas smooth, the upper florets conspicuously papillose in macroscopic observation (papillae 20–40 ␮m diam); inflorescences with 2, rarely 3, primary branches ...... P. ellipticum Döll 2. Leaf blades junciform, elliptical in cross section, solid, 1.5–2 mm wide; spikelets lanceolate, mostly 4 mm long., upper glumes and lower lemmas acute-acuminate, longer than the upper floret; lower lemmas wrinkled between nerves; upper florets inconspicuously papillose in macroscopic observation (papillae 10–15 ␮m diam); inflorescences with 2–7 primary branches ...... P. veredense nov. sp.

Paspalum clipeum G. H. Rua, Valls, Graciano-Ribeiro, & R. glabrous. Inflorescences formed by 1 or 2 (if two, separated C. Oliveira, sp. nov.— TYPE (here designated): BRAZIL. by an internode 0.8–1 cm long), erect racemes 1–2 cm long, Goiás: Mun. Simolândia, pouco ao norte da estrada Si- partly enclosed within the uppermost foliage leaf, main axis molândia-Jaciara, entrando a oeste da ponte sobre o cór- up to ca. 1 cm long; pulvini pilose; rachis of the racemes rego Salobro, 14°29Ј22.7Љ S, 46°29Ј42.3Љ W, 500 m, 28 May 0.8–0.9 mm wide, glabrous, slightly flexuous, triquetrous, 2006, J. F. M. Valls, G. H. Rua, A. Custodio 15204 (holo- narrowly 3–winged, ending in a terminal spikelet, green; type: CEN!; isotypes: BAA!, K!, L!, MO!, RB!, SI!, US!). pedicels 1–1.2 mm long, glabrous to puberulous, terete. Spikelets 2.4–2.5 mm long, 1.8–2.3 mm wide, suborbicular to P. convexo Humb. & Bonpl. ex Flüggé affine sed flosculo broadly obovate, paired, crowded, deciduous at maturity, superiori stramineo differt. sharply plano-convex (gibbous). Lower glumes lacking. Up- Dwarf annuals. Culms 3–11 cm tall, 0.5–1.1 mm diam, erect per glumes as long as the spikelets, suborbicular to broadly to ascending, freely branching and flowering from the axils obovate, cucullate, membranous, pale green, 5-nerved, of proximal leaves, the successive branches arising from the nerves prominent, light green, the lateral ones close to the axils of the prophylls forming cymose branching systems; margins, region between nerves with a few short hairs in the internodes 3–4, glabrous, solid, the basalmost purple-tinged; middle portion, otherwise glabrous, the margins clasping the nodes glabrous, purple-tinged. Leaf sheaths 2–6 cm long, dis- margins of the lower lemma, the base attenuate, the apex tally keeled, striate, glabrous to distally hirsute. Ligule 0.7– rounded. Lower lemmas as long as the upper glume, broadly 0.9 mm long, membranous, truncate to rounded, glabrous, obovate, flat, glabrous, the margins clasping the upper floret, without a pseudoligule. Blades 3–5 cm long, ca. 5 mm wide, rounded at apex, 5-nerved, the lateral nerves close to the lanceolate-acuminate, flat, the base slightly broader than the margins. Upper florets broadly obovate to suborbicular, as leaf sheath; hirsute to glabrescent with hirsute margins; up- long as the spikelet, sharply plano-convex (gibbous), strami- per blades reduced. Peduncles 1.5–4 cm long, compressed, neous, crustaceous, glabrous, the upper lemmas faintly 5–nerved, the thickened borders of the lemma clasping the palea borders, the paleas with overlapping marginal flaps, verrucose-reticulate at the internal surface; lodicules 2; stamens 3, anthers ca. 0.8 mm long, yellow, purple-tinged; stigmas 2, purple, plumose. Caryopsis ca. 1.6 mm long, 1.3 mm wide, plano-convex, broadly obovate, pale; hilum ca. 0.8 mm long, linear. Figures 5C, 8. Leaf Anatomy—(Fig. 9A, B). Leaf blade V-shaped in cross section, with smooth margins. Midrib conspicuous, containing a single first order vascular bundle towards the abaxial surface. Cuticle thin. Upper epidermis with typical epider-

FIG.8. Paspalum clipeum (from Valls et al. 15204). A. Habit. B. Spikelet, adaxial view. C. Spikelet, abaxial view. D. Spikelet, lateral view. E. Upper FIG. 9. Leaf blade anatomy in cross section, general view (left) and floret, abaxial view. F. Upper floret, adaxial view. G. Upper palea and detail of a portion (right). A, B. Paspalum clipeum (Valls et al. 15204). C, D. lodicules. H. Caryopsis, embryo side. I. Caryopsis, hilum side. Paspalum spissum (Rua et al. 798). 274 SYSTEMATIC BOTANY [Volume 33 mal cells, bicellular microhairs, short macrohairs, cushion Etymology—The epithet means ‘medal-like’, and refers to hairs, 3 fan-shaped bulliform cells, stomata, and silicified the shape of the spikelet. cells. Mesophyll consisting of radial chlorenchymatous cells. Observations—Paspalum clipeum is morphologically simi- Three orders of vascular bundles present, all of them sur- lar to P. convexum Humb. & Bonpl. ex Flüggé and other an- rounded by a single bundle sheath of relatively large, thin- nual species of the ‘Plicatula’ group (Oliveira 2004), with walled parenchyma cells. Bundles separated by 2 paren- which it shares the gibbous, sharply indurate upper florets, chyma cells. Abaxial and adaxial sclerenchyma caps associ- and the caryopses with linear hilums. However, P. clipeum ated with first-order vascular bundles. differs from other species in this group by having stramine- Distribution and Habitat—The new species was found in ous rather than dark brown upper florets. the vicinity of Simolândia, in the state of Goiás, in grazed The following key separates the new species from other areas surrounding deciduous woodlands locally known as annual South American Paspalum species with glabrous ‘matas secas’ (Fig. 3). Paspalum clipeum is known only from spikelets, inflorescences with rachis narrower than 2 mm the type collection. wide, and upper florets closed at the summit.

1. Upper glume wanting or reduced, not more than half as long as the spikelet ...... 2 2. Upper glume 1/3 to half as long as the spikelet, clasping; upper floret nearly smooth, marmorate-speckled ...... P. marmoratum Kuhlm. 2. Upper glume wanting or reduced to a small scale; upper floret conspicuously papillose, uniformly colored ...... Paspalum ‘Gardneriana’ group 1. Upper glume as long as the spikelet or nearly so ...... 3 3. Spikelets shield-shaped or provided of a broad notched margin ...... 4 4. Spikelets orbicular, with a broad notched margin ...... P. fimbriatum Kunth 4. Spikelets shield-shaped, without a notched margin ...... P. scutatum Nees ex Trin. 3. Spikelets variously shaped, but not shield-shaped or provided of a broad notched margin ...... 5 5. Upper floret dark brown ...... Paspalum ‘Plicatula’ group p.p. 5. Upper floret stramineous ...... 6 6. Spikelets up to 1.5 mm long ...... 7 7. Racemes 6 or more...... P. microstachyum J. Presl 7. Racemes 1–4...... Paspalum ‘Parviflora’ group p.p. 6. Spikelets more than 1.9 mm long ...... 8 8. Leaf sheaths coarsely pilose. Spikelets ca. 2 mm long, upper glume and lower lemma purple-mottled ...... P. expansum Döll 8. Leaf sheaths glabrous to distally hirsute. Spikelets ca. 2.5 mm long, upper glume and lower lemma uniformly pale green ...... P. clipeum nov. sp.

PASPALUM SPISSUM Swallen, Phytologia 14: 358. 1967.—TYPE: spikelets 4.4–5.2 mm long, solitary, densely imbricate in 2 BRAZIL. Maranhão: Carolina to San Antonio de Balsas, series, dorsiventrally compressed. Lower glumes lacking. 20–25 Mar 1943, J. R. Swallen 4050 (holotype: US-1612651, Upper glumes as long as the spikelets, 1.5–1.7 mm wide, photograph!). narrowly ovate, hyaline, pale, 3-nerved, the lateral nerves submarginal, densely silky-pilose on the basal third and Caespitose perennials forming loose clumps, the base of along the margins, the hairs up to 4 mm long, otherwise the tillers forming short, knotted, curved rhizomes sheltered glabrous, proximally convex, distally flattened, the proximal by numerous cataphylls that are covered with very dense, portion of the margins covering the margins of the lower villous to woolly, isabelline to tawny hairs on the outer sur- lemma, the base truncate, the apex acute. Lower lemmas 3.9– face. Culms 70–90 cm tall, 1.5–2 mm diam, erect; internodes 4.9 mm long, 1.1–1.2 mm wide, narrowly ovate to narrowly 11–16, hollow, the basal internodes 4–5 cm long, the distal elliptical, acute to rounded at apex, 3-nerved, flat, with internodes up to ca. 15 cm long; nodes generally white- folded margins, the indumentum as in the upper glume but bearded. Leaves mostly cauline, appressed along the culms the hairs shorter. Upper florets narrowly ovate, 3.3–3.8 mm and covering them. Leaf sheaths 4–8 cm long, decreasing long, 1.1–1.7 mm wide, plano-convex, distally flattened, acute toward the middle portion of the culm, those of basal leaves soft hairy, those of cauline leaves apically hirsute, otherwise to rounded at apex, cartilaginous, pale stramineous, faintly glabrous. Ligules 0.7–0.9 mm long, membranous, rounded, papillose, the upper lemmas pubescent at apex, the palea glabrous, erose, pseudoligule present. Blades up to ca. 15 cm glabrous, the apex not enclosed by the lemma apex; lodicules long, decreasing toward apex, 3–4 mm wide, narrowly trian- 2; stamens 3, anthers 2.4–2.5 mm long, purple-tinged; stigmas gular, flat, the base continuing with the sheath, the apex long 2, purple, plumose. Caryopses not seen. Figure 10. acuminate, coarsely tuberculate-hirsute on both surfaces. Pe- Leaf Anatomy—(Fig. 9C, D). Leaf expanded in cross sec- duncles 18–32 cm long, flattened, glabrous, pale. Inflores- tion. Midrib inconspicuous, containing a single first-order cences exserted or basally enclosed by the uppermost leaf vascular bundle more lignified than the others. Cuticle very sheath; main axis up to ca. 4 cm long, truncate, sometimes thick. Adaxial epidermis with typical epidermal cells, bicel- ending in a short membranous, scale-like appendix; ‘ra- lular microhairs, prickles, hooks, short macrohairs with cemes’ 7–14 cm long, 1 or 2(−3), separated by filiform inter- round apices and long macrohairs with acute apices, bulli- nodes 2–3 cm long, ascending; pulvini hirsute, frequently form cells, stomata, and silicified cells; abaxial epidermis flanked by two lateral membranous scales; rachis of the ra- lacking macrohairs and bulliform cells. Mesophyll consisting cemes 2–2.2 mm wide, glabrous, laterally winged, ending in of radial parenchyma cells. Three orders of vascular bundles a spikelet, the mid portion flexuous, composed of a thick, present, all with a single bundle sheath of relatively large, pale-green midnerve flanked by 2 or 3 thin, dark-green lat- thin-walled parenchyma cells. Bundles separated by 2 par- eral nerves, the wings ca. 0.8 mm wide, ferruginous, mi- enchymatous cells. Sclerenchyma extensions adaxial and ab- nutely scaberulous at margins; pedicels short, glabrous; axial in first-order vascular bundles, only abaxial in second- 2008] RUA ET AL.: NEW PASPALUM FROM BRAZIL 275

Pereira-Silva 4088 (CEN); Gerais de Balsas, estrada para Riachão, ca. 10.7 km de Gerais, 08°27Ј04Љ S, 46°43Ј27Љ W, 560 m, 20 Mar 2000, Oliveira et al. 1409 (CEN); Gerais de Balsas, ca. 16 km Gerais de Balsas-Riachão, 08°26Ј48Љ S, 46°40Ј11Љ W, 550 m, 20 Mar 2000, Oliveira et al. 1420 (CEN); Mato Grosso: Mun. Ribeirão Cascalheira, Royal Geographic Society Ex- pedition, Base Camp., 12°49Ј S, 51°46Ј W, 1967–69, Smith L11 (UB); To- cantins: Mun. Aguiarnópolis, km 64 da BR-226 cerca de 7 km a nordeste de Vanderlândia, 06°50Ј S, 47°54Ј W, 16 Mar 1985, Valls et al. 8339 and 8340 (CEN); Mun. Mateiros, Estação biológica do Jalapão, atalho na estrada Cnia. Panambi-Mateiros, 16 km antes do encontro com a estrada principal, 170 km de Dianópolis, 10°43Ј35.8Љ S, 46°12Ј48.3Љ W, 686 m, 7 Mar 2006, Rua et al. 774 (CEN); Região do Jalapão, estrada Mumbuca-Boa Esperança, 2 km antes do posto da Naturatins, 10°23Ј21.5Љ S, 46°36Ј03.7Љ W, 547 m, 8 Mar 2006, Rua et al. 779 (CEN); Região do Jalapão, estrada Mumbuca-Boa Esperança, morrinho no sopé da Serra do Espírito Santo, 8,5 km do povoado da Mumbuca, 10°23Ј38.3Љ S, 46°36Ј45.7Љ W, 500–550 m, 9 Mar 2006, Rua et al. 798 (CEN). Observations—In the comments of the original descrip- tion, Swallen (1967) pointed out that P. spissum differs greatly from the related species P. carinatum Humb. & Bonpl. ex Flüggé, because the former has “flat appressed blades com- pletely covering the culm, conspicuously villous cataphylls, and very narrow margins on the racemes”. Denham et al. (2002) considered P. spissum to be a synonym of P. carinatum, since width and pilosity of the leaf blade were thought to be highly variable characters across the collections examined. The occurrence of cauline leaves was attributed to the prob- able absence of periodic fires (Denham et al. 2002). Never- theless, cauline papillose-hispid leaf blades 2–3 mm wide on a many-noded culm occur consistently in all specimens of P. spissum examined, as well as culms having a knotted base with villous cataphylls forming a rather loose clump. These FIG. 10. Paspalum spissum (from Rua et al. 774). A. Habit. B. Portion of the rachis with spikelets, adaxial view. C. Spikelet ending the rachis. D. characteristics were also observed during fieldwork by GHR Spikelet, adaxial view. E. Spikelet, abaxial view. F. Upper glume, adaxial in recently burned Cerrado where individuals of P. carinatum view. G. Lower lemma, abaxial view. H. Upper floret, adaxial view. I. were growing a few meters away from individuals of P. spis- Upper floret, abaxial view. sum, generally associated with more disturbed habitats, such as roadside areas. Here, individuals of P. carinatum formed order vascular bundles. Adaxial sclerenchyma girders asso- dense tufts that contrast sharply with those of P. spissum, ciated just with first order vascular bundles. primarily because the former species has basal filiform leaves Distribution and Habitat—(Fig. 3). Paspalum spissum is a and few-noded culms (Fig. 5D). In this locality, plants of P. common species in sandy soils of Cerrado vegetation and is carinatum flowered earlier than those of P. spissum. Even found in the Brazilian states of Goiás, Maranhão, Mato though both species apparently have identical spikelets, we Grosso, and Tocantins. think P. spissum should be maintained as a separate species, Additional Material Examined—BRAZIL. Goiás: Mun. Posse, Serra in agreement with Filgueiras (1993). Geral de Goiás, rio da Prata, ca. 6 km S of Posse, 800 m, 7 Apr 1966, Irwin et al. 14511 (IBGE); Maranhão: Mun. Balsas, Projeto Geral de Balsas, The following key separates P. spissum from other Pas- 07°35Ј S, 46°05Ј W, 300 m, 17 Nov 1997, Oliveira & Pereira-Silva 512 (IBGE); palum species in P. subgen. Ceresia with solitary spikelets and Condomínio Kissy lote 16, 06°36Ј57ЉS, 46°43Ј12Љ W, 470 m, 18 Mar 1999, rachises less than 3 mm wide.

1. Upper glumes winged, cordate at the base; inflorescence primary branches up to 11, conjugate or subdigitate...... Paspalum sect. Pectinata Chase ex Rodr.-Rodr. (p.p.) 1. Upper glumes not winged nor cordate; inflorescence primary branches just 1–3, scattered along the main axis ...... 2 2. Annuals; upper florets stipitate...... P. cachimboense Davidse, Morrone & Zuloaga 2. Perennials; upper florets not stipitate ...... 3 3. Tillers densely packed in dense clumps, without basal cataphylls; culms with 2–4-nodes; leaves basal with linear to filiform blades ...... 4 4. Rachis of the racemes 1.8–2.5(–3.5) mm wide, straight to subfalcate; upper glumes densely pilose on the proximal third, otherwise scaberulous; upper glumes and lower lemmas flat in the upper portion; leaf blades filiform, recurved at maturity...... P. carinatum Humb. & Bonpl. Ex Flüggé 4. Rachis of the racemes 1–1.6 mm wide, straight; upper glumes densely pilose on the proximal half, otherwise glabrous; upper glumes and lower lemmas slightly convex; leaf blades linear, erect at maturity...... P. goyasense Davidse, Morrone & Zuloaga 3. Tillers spreading, forming loose clumps, the knotted base covered with conspicuous villous cataphylls; culms with 11–16-nodes; leaves basal and cauline, appressed, covering the culm, with narrowly triangular-acuminate blades ...... P. spissum Swallen

ACKNOWLEDGMENTS. We are indebted to Silvia Denham for kindly reviewer for revising the final version of the manuscript; to Juarez P. making observations on Andean material of P. ceresia at SI for us, and for Amaral, Nilton F. Barbosa, Adriana R. Custodio, Isabel B. Figueiredo, helpful discussions regarding the circumscription of P. ceresia; to Tarciso João M. de Rezende, Maurício B. Sampaio, and Isabel B. Schmidt for S. Filgueiras for help with the Latin diagnoses; to Vinicius Vasconcelos for collaboration during the fieldwork; to the Mumbuca community for lo- creating the distribution map; to M. Cecilia Scoones for the excellent gistic support during the Jalapão expeditions; to Rosana Falcão for SEM illustrations; to Osvaldo Morrone, Paul M. Peterson and an anonymous facilities; to Bruno M. T. Walter for valuable comments and references 276 SYSTEMATIC BOTANY [Volume 33 about Cerrado vegetation, and to the curators of BAA, CEN, IBGE, SI, and (Poaceae: Paniceae), a new species from central Brazil. Novon 11: UB, for making material available. GHR especially thanks Taciana B. 36–39. Cavalcanti for her continuous, willing help. This work received financial Giussani, L. M., H. Cota-Sánchez, F. O. Zuloaga, and E. A. Kellogg. 2001. support through fellowships to GHR and JFMV from the “Conselho Na- A molecular phylogeny of the grass subfamily Panicoideae (Poaceae) cional de Desenvolvimento Científico e Tecnológico (CNPq)”, Brazil. shows multiple origins of C4 photosyntesis. American Journal of GHR is a member of the “Carrera del Investigador” of the “Consejo Botany 88: 1993–2012. Nacional de Investigaciones Científicas y Técnicas (CONICET)”, Argen- Mendonça, R. C., J. M. Felfili, B. M. T. Walter, M. C. Silva-Júnior, A. V. tina. Rezende, T. S. Filgueiras, and P. E. Nogueira. 1998. Flora vascular do Cerrado. Pp. 289−556 in Cerrado: ambiente e flora, eds. S. M. Sano & S. P. Almeida. Planaltina: EMBRAPA-CPAC. LITERATURE CITED Morrone, O. and F. O. Zuloaga. 2003. New species of Paspalum (Poaceae: Aliscioni, S. S. 2000. Anatomía ecológica de algunas especies del género Panicoideae: Paniceae) from Brazil. Systematic Botany 28: 307–312. Paspalum (Poaceae, Panicoideae, Paniceae). Darwiniana 38: 187–207. Oliveira, R. C. 2004. Estudo taxonômico das espécies de Paspalum L., Burman, A. G. 1980. A new species of Paspalum (Gramineae) from Brazil. grupo Plicatula (Poaceae-Panicoideae-Paniceae) no Brasil. Dr thesis, Kew Bulletin 35: 297–298. University of Campinas, Campinas, SP, Brazil. Clayton, W. D. and S. A. Renvoize. 1986. Genera Graminum. Kew Bulletin, Oliveira, R. C. and J. F. M. Valls. 2002. Taxonomia de Paspalum L., grupo Additional Series 13: 1–389. London: Her Majesty’s Stationery Office. Linearia (Gramineae - Paniceae) do Brasil. 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